where can i find slapper bars or whatever those are called under the vehicle for my 73 c-10 pickup truck? is it possible to fabricate some decent ones and weld them on and whatnot? are there any aftermarket companies that sell these slapper bars?

A universal set of slapper bars may still be available. I do not know who still makes them; back in the 1970's they seemed to be everywhere, with many different manufacturers.

The problem with such bars is they limit suspension travel.

Try looking at companies that sell suspension kits for '73-'87 Chev 4x4 trucks. Some manufacturers made had bolt - on link kits that limit leaf spring wind - up without limiting travel.

ill have to look into that. yeah i dunno if i really need a lot of suspension travel, my wider tires i will get would rub probably anyways